This disclosure relates generally to wireless optical telecommunication systems, and in particular but not exclusively, relates to a transceiver that is usable in a wireless optical telecommunication system.
At a basic level, a typical wireless optical telecommunication system comprises an optical transmitter and an optical receiver, with associated electronics to modulate and demodulate data on a light beam. Often, receivers are basically telescopes, while transmitters sometimes comprise units that are located separately from the receiver.
These optical transmitter and receiver units may have many parts, thereby contributing to the overall size or xe2x80x9cfootprintxe2x80x9d of the units. The individual parts themselves may also have a large footprint. This increased footprint can be detrimental in situations where the units need to be installed in a non-obtrusive manner. The increased footprint can also disadvantageously limit the amount of available space, within the housing of the transmitter or receiver units, in which to fit the various parts or components.
These optical transmitter and receiver units can also be difficult to align properly during installation and during use. Furthermore, the various optics and components of typical optical transmitters and optical receivers are heavy, fragile, bulky, and difficult to manufacture with consistent quality, and are often expensive. Because optical communications systems are capable of much higher data rates than traditional radio frequency (RF) systems, the ability to make stable and inexpensive systems is becoming more and more desirable.
According to an aspect of the invention, an apparatus provides a holographic optical element (HOE) device that is disposed in a receiver unit. The HOE device includes an interference pattern recorded on an emulsion material. A transmitter unit is disposed at least in part behind the HOE device. The emulsion material is shaped to allow transmission of a light signal from the transmitter unit through the HOE device, substantially unaffected by the recorded interference pattern.